10 Gigabit Ethernet (10GbE) is a set of Ethernet standards with a nominal data rate of 10 Gbit/s. 10GbE over fiber, copper cabling and twisted pair are specified by the IEEE 802.3 standard IEEE 802.3 is a collection of standards defining the physical layer, and the media access control (MAC) sublayer of the data link layer for wired Ethernet. IEEE 802.3ap, for example, provides a standard for Backplane Ethernet over printed circuit boards, with rates of 1 and 10 Gbit/s
The IEEE 802.3ap standard defines the physical medium dependent sublayer (PMD) control function. The PMD control function implements the 10GBASE-KR start-up protocol, which provides a mechanism through which the local receiver can tune the link-partner transmit equalizer to optimize performance over the backplane interconnect, and to inform the link partner when training is complete and it is ready to receive data. This mechanism is implemented through the continuous exchange of fixed-length training frames. These training frames are used by the two physical layer devices to exchange control and status information necessary to configure the adaptive equalization filters for both devices. The training frames include a header, a coefficient update field, a status report field, and a PN11 training pattern field
The IEEE 802.3ap standard does not define the usage of the PN11 training pattern field by the receiver. In order to equalize a backplane, the receiver designer typically allocates the equalization burden between both the receiver and the transmitter. The equalization is evaluated based on one or more predefined criteria. Generally, the transmitter equalization time is limited and the equalization space is vast. Thus, conventional equalization criterions are sub-optimal and ate not suitable for IEEE 802.3ap applications. A need therefore exists for improvements in the equalization speed